I am totally impressed with the RCF80. I am working on setting up an 80-meter capable FT8 100 watt field station, as was struggling with a configuration that was portable, small(ish) and allowed for repeatable results. I tried loops, Isotrons, random wires, loaded verticals. Nothing seemed to be the perfect fit.
I purchased a pair of RCF80's to run in a "V" configuration and I couldn't more pleased. Yes, the SWR curve is razor-sharp, but once tuned, it is perfectly repeatable. I am able to get down to a 1:1.4 SWR and make casual contacts out to about 1,500 miles on 80 meters.
Two things to note: (1) I uses a balun to feed the 50ohm coax, and it gets a bit warm at 100w....I need to upgrade that. and (2) it would be nice if the whip was just a few inches longer. I can hit the 3.573 FT8 segment on the lower end of 80 meters, but it requires every inch of available whip...I wish I had a bit of headroom.
All-in-all? A cost effective way to run a quick set-up field antenna on 80 meters. Mission completed!